#115 The Science of Blueberries for Brain and Vascular Health

Rhonda Patrick, Ph.D. (0:00)

Welcome back to the podcast. Today, we're going to talk about blueberries. We're going to cover how blueberries improve vascular function, how they protect the brain, improve glucose control, repair the gut, and may even help with exercise recovery. Then there's the banana smoothie question. Why I think leaving ripe bananas out of a blueberry smoothie is a reasonable optimization. By the end of this episode, you'll know where the benefits look most credible, where the science is still preliminary, and how to build a simple blueberry habit without turning this useful food into a miracle cure. Before we get started, if you haven't already subscribed to my free weekly newsletter, you can sign up right now. You should sign up right now at foundmyfitness.com/newsletter.

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Thank you so much for your support, and let's get into all things blueberries.

One cup of blueberries per day may be enough to measurably change how your arteries function and perhaps influence how your brain ages. Blueberries improve the ability of your arteries to relax and deliver more blood to the brain, heart, and working muscles. The brain findings are especially intriguing. Blueberry interventions have improved aspects of memory and cognition in older adults, while long-term observational data have linked regular blueberry intake to a slower rate of cognitive decline, equivalent to actually being around 1.5 to 2.5 years younger cognitively. In this episode, I will examine what the human evidence actually shows for brain aging, blood flow, glucose regulation, gut health, inflammation, and exercise recovery. And this is not simply an antioxidant story. Blueberry anthocyanins are transformed into metabolites that act like biological singling molecules. They affect everything from nitric oxide to inflammation, gene expression, and even neuronal plasticity. I will also revisit the controversial blueberry and banana smoothie question, what the evidence really shows, where the uncertainty remains, and why I still take a cautious approach when trying to maximize blueberry polyphenol exposure. Before we get into health outcomes, I do think it's important to understand what makes blueberries so biologically interesting. So blueberries are often described as being high in antioxidants. But I do think that that can create the wrong mental model. So a direct antioxidant such as vitamin E, that is something that can physically interact with a reactive molecule, something like perhaps a reactive oxygen species. Then it can terminate this chain reaction that ends in oxidation. Blueberry polyphenols can also do that. They can neutralize oxidants. But I think that's probably not their most interesting primary role in the human body. Most blueberry polyphenols circulate at relatively low concentrations, and they're very much transformed by intestinal enzymes, by the gut microbiome, and also by the liver. So the resulting metabolites of those polyphenols actually behave less like antioxidant sponges, and they act more like signaling molecules. I've talked a lot about other signaling molecules before. These are chemical messengers. They transmit information between cells, and they coordinate various biological responses. So for example, I've talked about exercise-induced lactate, and how that increases brain drive neurotrophic factor in the brain. I've talked about ketones like beta-hydroxybutyrate, and how those can increase anti-inflammatory enzymes. Even peptides like BPC157 exert their healing through signaling mechanisms. So this is important because polyphenol metabolites are also signaling molecules. They can influence processes in the body like nitric oxide production, endogenous antioxidant defenses, inflammatory pathways, enzyme activity, gene expression, and on and on. So let's talk about the major polyphenols that are actually found in blueberries. First and foremost, anthocyanins. These are generally the dominant class. These are actually the pigments that are concentrated in blueberry skin that produce that dark blue and purple color. One cup of blueberries commonly provides roughly around 160 to 385 milligrams of anthocyanins, although I would say that really depends on the cultivation of the blueberries, the types of blueberries that we're talking about here, growing conditions, lots of things. However, anthocyanins also have the strongest direct human evidence, particularly for improving vascular function. We're going to talk more about that later.